National League MVP Ryan Braun has tested positive for a banned substance and is appealing to avoid a 50-game suspension, according to people familiar with the case.

ESPN cited two sources in first reporting the result, saying the Milwaukee Brewers slugger tested positive for elevated levels of testosterone, adding that a later test by the World Anti-Doping Agency lab in Montreal determined the testosterone was synthetic.

A spokesman for Braun said in a statement issued to ESPN and The Associated Press that "there are highly unusual circumstances surrounding this case which will support Ryan's complete innocence."

"There was absolutely no intentional violation of the program," Matthew Hiltzik said in a statement sent by the four-time All-Star left fielder's representatives.

"While Ryan has impeccable character and no previous history, unfortunately, because of the process we have to maintain confidentiality and are not able to discuss it any further, but we are confident that he will ultimately be exonerated," he said.

Major League Baseball does not announce positive tests and penalties in drug cases involving initial positives until all arbitration is concluded.

The case is still being appealed to an arbitrator under MLB's drug program, people familiar with the situation told the AP. The people spoke on condition of anonymity because the appeal is still ongoing and said Braun and others involved in the appeals process have known about the positive test since late October.

One of the people said the appeals process is not likely to be concluded until January at the earliest. That person also told the AP that after being informed of the positive test, Braun asked to have another urine test taken, and that the second test was within normal range.

If suspended, Braun wouldn't be eligible to play for the NL Central champions until May 31. He would miss the first 57 days of the major league season, losing about $1.87 million of his $6 million salary.

Brewers owner Mark Attanasio praised Braun as "a model citizen in every sense of the word" and "a person of character and integrity."

"We are dealing with an incomplete set of facts and speculation. Before there is a rush to judgment, Ryan deserves the right to be heard. We are committed to supporting Ryan to get to the truth of what happened in this unfortunate situation." Attanasio said in a statement, adding the team had no information from Major League Baseball about the case.

The 28-year-old Braun, the 2007 NL Rookie of the Year, hit .312 with 33 homers and 111 RBIs last season and led Milwaukee to the NL championship series, where the Brewers lost to the eventual World Series champion St. Louis Cardinals.

Braun already was signed through 2015 when the Brewers gave him a new deal running through 2020 that added $105 million and guaranteed him a total of $145.5 million over a decade.